Aquatic Ecology

, Volume 39, Issue 4, pp 419–430 | Cite as

Modification of the physical environment by an Ecklonia radiata (Laminariales) canopy and implications for associated foliose algae

  • Thomas Wernberg
  • Gary A. Kendrick
  • Benjamin D. Toohey


Macroalgal canopies modify their surrounding environment and thereby influence the structure of associated algal assemblages. Canopies can modify many factors that can be hard to separate and, consequently, the importance of individual factors often remains unknown. Experiments were carried out to test the hypotheses that Ecklonia radiata canopies modify light, sediment cover and water motion, and that each of these physical factors separately influence the assemblage of associated foliose algae. We measured light, sediment cover and water motion across six naturally occurring E. radiata densities and found a reduction in light and sediment cover as kelp density increased. The outcome for water motion was inconclusive. We also manipulated each of these three factors, while controlling for the two others, to determine the separate effects of light, sediment cover and water motion on the assemblage of foliose algae. Reduction in light had a strong effect on the foliose assemblage, reducing species richness and biomass. Reduction in sediment cover and water motion did not cause separate effects at the level of the assemblage, but the biomass of individual species of foliose algae indicated both positive and negative effects. We conclude that E. radiata canopies at Marmion, Western Australia, modify at least two factors of their physical environment, light and sediment cover. However, only light is modified to an extent where it has effects at the assemblage-level because, in contrast to the effects of sediment cover and water motion, the direction of responses are consistent among individual species of algae.


Canopy effects Canopy density Kelp Light Sediment cover Water motion 


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The Danish Natural Science Research Council and The Danish Research Academy provided financial support through grants to TW. TW also received financial support from Knud Hoejgaards Fond and Julie von Müllens Fond. We would like to thank the Department of Conservation and Land Management (CALM) Marine Conservation Branch, Perth, for permits to work at Marmion. We also would like to thank, M.A. Vanderklift, J.V. Riis, M.S. Thomsen and S. Kildesgaard for assistance in the field. M.A. Vanderklift and M.S. Thomsen are further acknowledged for valuable comments on early stages of this work and manuscript.


  1. Ackerman J.D., Okubo A. (1993) Reduced mixing in a marine macrophyte canopy. Funct Ecol 7:305–309CrossRefGoogle Scholar
  2. Airoldi L. (2003) The effects of sedimentation on rocky coast assemblages. Oceanogr Mar Biol 41:161–236Google Scholar
  3. Airoldi L., Cinelli F. (1997) Effects of sedimentation on subtidal macroalgal assemblages - an experimental study from a mediterranean rocky shore. J Exp Mar Biol Ecol 215:269–288CrossRefGoogle Scholar
  4. Airoldi L., Rindi F., Cinelli F. (1995) Structure, seasonal dynamics and reproductive phenology of a filamentous turf assemblage on a sediment influenced, rocky subtidal shore. Bot Mar 38:227–237CrossRefGoogle Scholar
  5. Benedetti-Cecchi L., Pannacciulli F., Bulleri F., Moschella P.S., Airoldi L., Relini G., Cinelli F. (2001) Predicting the consequences of anthropogenic disturbance: large-scale effects of loss of canopy algae on rocky shores. Mar Ecol Prog Ser 214:137–150CrossRefGoogle Scholar
  6. Berger R., Henriksson E., Kautsky L., Malm T. (2003) Effects of filamentous algae and deposited matter on the survival of Fucus vesiculosus L. germlings in the Baltic Sea. Aquatic Ecol 37:1–11CrossRefGoogle Scholar
  7. Bertness M.D., Leonard G.H., Levine J.M., Schmidt P.R., Ingraham A.O. (1999) Testing the relative contribution of positive and negative interactions in rocky intertidal communities. Ecology 80:2711–2726CrossRefGoogle Scholar
  8. Connell S.D. (2003) The monopolization of understorey habitat by subtidal encrusting coralline algae: a test of the combined effects of canopy-mediated light and sedimentation. Mar Biol 142:1065–1071Google Scholar
  9. Critchley A.T., De Visscher P.R.M., Nienhuis P.H. (1990) Canopy characteristics of the brown alga Sargassum muticum (Fucales, Phaeophyta) in Lake Grevelingen, southwest Netherlands. Hydrobiol 204/205:211–217CrossRefGoogle Scholar
  10. Daly M.A., Mathieson A.C. (1977) The effects of sand movement on intertidal seaweeds and selected invertebrates at Bound Rock, New Hampshire, USA. Mar Biol 43:45–55CrossRefGoogle Scholar
  11. D’Antonio C.M. (1986) The role of sand in the domination of hard substrata by the intertidal alga Rhodomela larix. Mar Ecol Prog Ser 27:263–275CrossRefGoogle Scholar
  12. Dayton P.K. (1985) Ecology of kelp communities. Ann Rev Ecol Syst 16:215–245CrossRefGoogle Scholar
  13. Dean T.A. (1985) The temporal and spatial distribution of underwater quantum irradiation in a southern California, USA, kelp forest. Estuar Coast Shelf Sci 21:835–844CrossRefGoogle Scholar
  14. Denny M. (1995) Predicting physical disturbance - mechanistic approaches to the study of survivorship on wave-swept shores. Ecological Monogr 65:371–418CrossRefGoogle Scholar
  15. Devinny J.S., Volse L.A. (1978) Effects of sediments on the development of Macrocystis pyrifera gametophytes. Mar Biol 48:343–348CrossRefGoogle Scholar
  16. Dudgeon S.R., Johnson S.A. (1992) Thick vs. thin thallus morphology and tissue mechanics influence differential drag and dislodgment of two co-dominant seaweeds. J Exp Mar Biol Ecol 165:23–43CrossRefGoogle Scholar
  17. Dudgeon S.R., Kubler J.E., Vadas R.L., Davison I.R. (1995) Physiological responses to environmental variation in intertidal red algae - does thallus morphology matter. Mar Ecol Prog Ser 117:193–206CrossRefGoogle Scholar
  18. Eckman J.E., Duggins D.O., Sewell A.T. (1989) Ecology of understory kelp environments i. effects of kelps on flow and particle transport near the bottom. J Exp Mar Biol Ecol 129:173–188CrossRefGoogle Scholar
  19. Edwards M.S. (1998) Effects of long-term kelp canopy exclusion on the abundance of the annual alga Desmarestia ligulata (Lightf). J Exp Mar Biol Ecol 228:309–326CrossRefGoogle Scholar
  20. Eriksson B.K., Johansson G., Snoeijs P. (2002) Long-term changes in the macroalgal vegetation of the inner Gullmar Fjord, Swedish Skagerrak coast. J Phycol 38:284–296CrossRefGoogle Scholar
  21. Fabricius K.E., Wolanski E. (2000) Rapid smothering of coral reef organisms by muddy marine snow. Estuar Coast Shelf Sci 50:115–120CrossRefGoogle Scholar
  22. Gerard V.A. (1984) The light environment in a giant kelp forest: influence of Macrocystis pyrifera on spatial and temporal variability. Mar Biol 84:189–195CrossRefGoogle Scholar
  23. Henley W.J., Ramus J. (1989) Optimization of pigment content and the limits of photoacclimation for Ulva rodundata (Chlorophyta). Mar Biol 103:267–274CrossRefGoogle Scholar
  24. Hurd C.L. (2000) Water motion, marine macroalgal physiology, and production. J Phycol 36:453–472CrossRefGoogle Scholar
  25. Irving A.D., Connell S.D. (2002) Sedimentation and light penetration interact to maintain heterogeneity of subtidal habitats: algal vs. invertebrate dominated assemblages. Mar Ecol Prog Ser 245:83–91CrossRefGoogle Scholar
  26. Isaeus M., Malm T., Persson S. and Svensson A. 2004. Effects of filamentous algae and sediment on recruitment and survival of Fucus serratus (Phaeophyceae) juveniles in the eutrophic Baltic Sea. Eur J. Phycol. 39: 301–307Google Scholar
  27. Jackson G.A., Winant C.D. (1983) Effect of a kelp forest on coastal currents. Cont Shelf Res 2:75–80CrossRefGoogle Scholar
  28. Jones C.G., Lawton J.H., Shachak M. (1994) Organisms as ecosystem engineers. Oikos 69:373–386CrossRefGoogle Scholar
  29. Keddy P.A. (1992) Assembly and response rules two goals for predictive community ecology. J Vegetation Sci 3:157–164CrossRefGoogle Scholar
  30. Kendrick G.A. (1991) Recruitment of coralline crusts and filamentous turf algae in the Galapagos archipelago Pacific Ocean effect of simulated scour, erosion and accretion. J Exp Mar Biol Ecol 147:47–64CrossRefGoogle Scholar
  31. Kendrick G.A., Lavery P.S., Philips J.C. (1999) Influence of Ecklonia radiata kelp canopy structure on macro-algal assemblages in Marmion Lagoon, Western Australia. Hydrobiol 399:275–283CrossRefGoogle Scholar
  32. Kendrick G.A., Harvey E., Wernberg T., Harman N., Goldberg N. (2004) The role of disturbance in maintaining diversity of benthic macroalgal assemblages in southwestern Australia. Jap J Phycol (Suppl) 52:5–9Google Scholar
  33. Kennelly S.J. (1987) Physical disturbances in an Australian kelp community: ii effects on understorey species due to differences in kelp cover. Mar Ecol Prog Ser 40:155–165CrossRefGoogle Scholar
  34. Kennelly S.J. (1989) Effects of kelp canopies on understorey species due to shade and scour. Mar Ecol Prog Ser 50:215–224CrossRefGoogle Scholar
  35. Kennelly S.J., Underwood A.J. (1993). Geographic consistencies of effects of experimental physical disturbance on understorey species in sublittoral kelp forests in central New South Wales. J Exp Mar Biol Ecol 168:35–58CrossRefGoogle Scholar
  36. King R.J., Schramm W. (1976) Photosynthetic rates of benthic marine algae in relation to light intensity and seasonal variations. Mar Biol 37:215–222CrossRefGoogle Scholar
  37. Kirkman H. (1981) The first year in the life history and the survival of the juvenile marine macrophyte, Ecklonia radiata (Turn) J Agardh. J Exp Mar Biol Ecol 55:243–254CrossRefGoogle Scholar
  38. Komar P.D., Miller M.C. (1973) The threshold of sediment movement under oscillatory water waves. J Sed Petrology 43:1101–1110Google Scholar
  39. Leliaert F., Anderson R.J., Bolton J.J., Coppejans E. (2000) Subtidal understorey algal community structure in kelp beds around the cape peninsula (western cape, South Africa). Bot Mar 43:359–366CrossRefGoogle Scholar
  40. Lobban C.S., Harrison P.J. (1994) Seaweed ecology and physiology. Cambridge University Press, Cambridge, 366 ppGoogle Scholar
  41. Lüning K. (1981) Light. In: Wynne M.J. (ed) The biology of seaweeds. Blackwell Scientific, Oxford, pp. 326–355Google Scholar
  42. Markager S., Sand-Jensen K. (1992) Light requirements and depth zonation of marine macroalgae. Mar Ecol Prog Ser 88:83–92CrossRefGoogle Scholar
  43. Melville A.J., Connell S.D. (2001) Experimental effects of kelp canopies on subtidal coralline algae. Aust Ecol 26:102–108CrossRefGoogle Scholar
  44. Phillips J.C., Kendrick G.A., Lavery P.S. (1997) A test of a functional group approach to detecting shifts in macroalgal communities along a disturbance gradient. Mar Ecol Prog Ser 153:125–138CrossRefGoogle Scholar
  45. Santelices B., Ojeda F.P. (1984) Effects of canopy removal on the understory of algal community structure of coastal forests of Macrocystis pyrifera from southern South America. Mar Ecol Prog Ser 14:165–173CrossRefGoogle Scholar
  46. Schiel D.R., Foster M.S. (1986) The structure of subtidal algal stands in temperate waters. Oceanogr. Mar Biol Ann Rev 24:265–307Google Scholar
  47. Searle D.J., Semeniuk V. (1985) The natural sectors of the inner Rottnest shelf coast adjoining the Swan coastal plain. J Royal Soc Western Australia 67:116–136Google Scholar
  48. Shaughnessy F.J., DeWreede R.E., Bell E.C. (1996) Consequences of morphology and tissue strength to blade survivorship of two closely related rhodophyta species. Mar Ecol Prog Ser 136:257–266CrossRefGoogle Scholar
  49. Stewart J.G. (1983) Fluctuations in the quantity of sediments trapped among algal thalli on the intertidal rock platforms in southern California. J Exp Mar Biol Ecol 73:205–211CrossRefGoogle Scholar
  50. Toohey B.D., Kendrick G.A., Wernberg T., Phillips J.C., Malkin S., Prince J. (2004) The effects of light and thallus scour from Ecklonia radiata canopy on an associated foliose algal assemblage: the importance of photoacclimation. Mar Biol 144:1019–1027CrossRefGoogle Scholar
  51. Velimirov B., Griffiths C.L. (1979) Wave-induced kelp movement and its importance for community structure. Bot Mar 22:169–172CrossRefGoogle Scholar
  52. Vogt H., Schramm W. (1991) Conspicuous decline of Fucus in Kiel Bay Western Baltic what are the causes. Mar Ecol Prog Ser 69:189–194CrossRefGoogle Scholar
  53. Wernberg T., Kendrick G.A., Phillips J.C. (2003) Regional differences in kelp-associated algal assemblages on temperate limestone reefs in south-western Australia. Diversity and Distributions 9:427–441CrossRefGoogle Scholar
  54. Wood W.F. (1987) Effect of solar uv radiation on the kelp Ecklonia radiata. Mar Biol 96:143–150CrossRefGoogle Scholar
  55. Worcester S.E. (1995) Effects of eelgrass beds on advection and turbulent mixing in low current and low shoot density environments. Mar Ecol Prog Ser 126:223–232CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, Inc. 2005

Authors and Affiliations

  • Thomas Wernberg
    • 1
    • 2
  • Gary A. Kendrick
    • 1
  • Benjamin D. Toohey
    • 1
  1. 1.School of Plant Biology, Botany building MO90University of Western AustraliaCrawleyAustralia
  2. 2.Centre for Ecosystem Management, Bldg 19Edith Cowan UniversityJoondalupAustralia

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